Soil and stain resistance and soil and stain release properties in textile articles

ABSTRACT

TEXTILE ARTICLES OF CELLULOSIC FIBERS, OF NON-CELLULOSIC FIBERS AND COMPRISING BLENDS OF CELLULOSIC AND NON-CELLULOSIC FIBERS, WITH IMPROVED SOIL AND STAIN RESISTANCE QUALITIES, AND WITH MINIMISED ODOR AND TOXICITY IN THE FINISHED PRODUCT, ARE PRODUCED BY CONTACTING THE ARTICLES WITH CONVENTIONAL PRESS-FREE CREASE-RETENTION TERMOSETTING RESIN FINISH REACTANTS CONTAINING AN ALDEHYDE OR FROM WHICH AN ALDEHYDE IS RELEASED DURING POLYMERIZATION THEREOF, ANIMAL GLUE, AND A PLASTICIZER; AND BY CURING THE RESIN.

United States PatentO 3,582,257 SOIL AND STAIN RESISTANCE AND SOIL AND STAIN RELEASE PROPERTIES IN TEXTILE ARTICLES Julian J. Hirshfeld and Bertie J. Reuben, Decatur, and

John W. Bullington, Athens, Ala., assignors to Monsanto Company, St. Louis, M0. N Drawing. Filed May 10, 1968, Ser. No. 728,340 Int. Cl. D06; D06m 9/00 US. Cl. 8115.6 13 Claims ABSTRACT OF THE DISCLOSURE Textile articles of cellulosic fibers, of non-cellulosic fibers and comprising blends of cellulosic and non-cellulosic fibers, with improved soil and stain resistance qualities, and with minimised odor and toxicity in the finished product, are produced by contacting the articles with conventional press-free crease-retention thermosetting resin finish reactants containing an aldehyde or from which an aldehyde is released during polymerization thereof, animal glue, and a plasticizer; and by curing the resin.

BACKGROUND OF THE INVENTION This invention relates to textile articles including fabrics consisting essentially of cellulosic fibers or of non-cellulosic fibers and fabric blends of both, and more particularly to a process for finishing textile articles including fabrics whereby soil and stain resistance and soil and stain release properties are enhanced.

Conventional press-free, wrinkle-free or permanent press fabric finishing, as is known in the art, involves treating textile articles comprising cellulosic fibers, and preferably blends of cellulosic fibers and non-cellulosic fibers, with a resin. Although thermoplastic resins are sometimes used, this invention relates to the use of thermosetting materials in a process for imparting to a fabric or a garment the abiilty to retain its total shape-retaining properties indefinitely. When heated, these thermosetting materials react with a cellulosic substrate and/or with themselves to form insoluble, nonsoftening cross-links and resins in place. Many of the thermosetting materials contain formaldehyde or release formaldehyde when polymerized. This liberation of free aldehyde has presented a serious odor and toxicity problem with the use of such resin-forming materials as urea-formaldehyde monomers; ethyl, methyl and hydroxy ethyl carbamates; the triazones; the melamines; as well as the presently popular dimethylol, dihydroxy ethylene urea and dimethylol propylene urea. The relative desirability of the use of these resins has, in fact, been rated according to the amount of formaldehyde released.

As a general rule, fabrics finished with resins to create a permanent press are more easily soiled and have a tendency to resist stain removal, especially where the stains are of an oily or greasy nature. Fabrics which are blends of cellulosic fibers and non-cellulosic fibers are especially vulnerable to soiling and most resistant to soil and stain removal. This problem has been of great concern to dyers and finishers particularly as applied to white or light colored fabrics.

SUMMARY OF THE DISCLOSURE It is a primary object of this invention to provide a process for improving soil and stain resistance and soil and stain release properties in textile articles, including fabrics consisting of cellulosic fibers, and/ or non-cellulosic fibers,

3,582,257 Patented June 1., 1971 It is a secondary object of this invention to provide for the removal by absorption of free formaldehyde released during the curing of certain thermosetting resins.

These and other objects and advantages will become apparent in the course of the following specification, examples and appended claims.

Briefly, the objects of this invention are accomplished in a press-free system by applying to the artcile a mixture of a thermosetting resin-forming material which contains formaldehyde or releases formaldehyde upon polymerization, a catalyst if required, animal glue or gelatin, and a plasticizer such as sorbitol or glycerine; and then curing the resin.

DESCRIPTION OF THE PREFERRED EMBODIMENT The term textile article is meant to include fiber, yarn, all types of fabric, all types of carpets, and any textile article made of fiber. The textile article can be comprised of a natural fiber, a synthetic fiber or a combination of a natural and a synthetic fiber. Other types of material useful in textile articles and of common knowledge to the textile art may be present in minor portions. Examples of useful natural fibers include cotton, wool, silk, etc. The term synthetic fiber is meant to include all truly synthetic fibers and all man-made fibers. Examples of synthetic fibers include rayon fiber (a manufactured fiber composed of regenerated cellulose as well as manufactured fibers composed of regenerated cellulose in which substituents have replaced not more than 15% of the hydrogens of the hydroxyl groups), acetate fiber (a manufactured fiber in which the fiber-forming substance is cellulose acetate; where not less than 92% of the hydroxyl groups are acetylated, the term tri-acetate may be used as a generic description of the fiber), spandex fiber (a manufactured fiber in which the fiber-forming substance is any longchain synthetic polymer of at least by weight of a segmented polyurethane), polyester fiber (a manufactured fiber in which the fiber-forming substance is any longchain synthetic polymer composed of at least 85% by weight of an ester of a dihydric alcohol and a dibasic acid or derivative thereof, such as terephthalic acid and dimethyl terephthalate), olefin fiber (a manufactured fiber in which the fiber-forming substance is any long-chain synthetic polymer composed of at least 85% by weight of ethylene, propylene or other olefin units), modacrylic fiber (a manufactured fiber in which the fiber-forming substance is any long-chain synthetic polymer composed of less than 85 but at least 35% by weight of acrylonitrile units), nylon fiber (a manufactured fiber in which the fiber-forming substance is any long-chain synthetic polyamide haying recurring amide groups as an integral part of the polymer chain), and acrylic fiber (a manufactured fiber in which the fiber-forming substance is any longchain synthetic polymer composed of at least 85% by weight of acrylonitrile units).

The application of this invention is not restricted to a method of curing of the resin. Some of the resins mentioned herein are known in the art to be suitable for use in deferred curing processes; and some are known to be limited in use to pre-cured processes. Either process can be employed subject to material qualifications and limitations well known to those skilled in the textile art.

Not all resins and reactants which are used commercially to impart wrinkle-free properties to fabrics are suitable to the application of the instant invention.

Only those resins and reactants which contain aldehyde or in the curing process, release aldehyde to a greater or lesser extent, may be used without further addition of formalin or other aldehyde-releasing compounds. As used herein, unless otherwise indicated, the term aldehyde-releasing resin includes resin reactants containing a free aldehyde as well as those forming an aldehyded when heat-cured. In either case free aldehyde is given off. The extent that free aldehyde is released during the curing process is, of course, determined by the particular resin reactants employed and by the conditions to which these reactants are subjected. Included within this group are the following:

(1) The urea-formaldehydes such as monomethylol urea NH-CHzOH 0=c i H NNH dimethylol urea NH-CHzOH o=o NH-CHzOH and trimethylol urea l CHzOH 0:0 emon NH-CHzOH which are produced from urea and formaldehyde, are used as reactants with formaldehyde, and release formaldehyde on curing.

w.) (2) The melamine-formaldehydes including trimethylol and hexamethylol isomelamine HO CHrN p=NcmoH Like the urea-formaldehydes, the melamine-formalde hydes are normally produced in the presence of formal- 75 dehyde, the amount of formaldehyde controlling the degree of substitution in the condensing reaction. In the condensation to form resin, formaldehyde will be evolved with the use of each but considerably more will be evolved with the use of hexamethylol derivatives since there is no remaining N-hydrogen.

(3) The propylene ureas including dimethylol propylene urea and dihydroxy dimethylol propylene urea (4) The imidazolidones, made from urea and glyoxal, the most common of which used is dihydroxy dimethylol ethylene urea ca o no CHr-N N-onmn HOCHH on (5) The carbamates including dimethylol ethyl carbamate and dimethylol methyl carbamate as well as dimethylol isopropyl carbamate HO CE: (H) /CH3 /NC-CH HO CH3 CH3 [6) The urons including dimethylol uron and dimethyl N-methylol uron (7) The triazones including ethyl triazone and (8) The acetals.

In connection with the use of the above finishing reactants, it is only necessary that sufficient free aldehyde is released during the curing process to solidify the gelatin.

The techniques of employment of each is within the knowledge of those skilled in the art. We have found that with respect to these reactants, their use in quantities ordinarily employed in the art, will provide sufficient free aldehyde to solidify any useful amounts of animal glue. To provide a finish mixture in which substantially all formaldehyde is eliminated by absorbtion, it is necessary to determine the glue-resin ratio experimentally with respect to each resin. Where absorbtion of substantially all formaldehyde would require excessive amounts of glue, the elimination of odor by this method would, of course, be impractical.

The methylol resin-forming monomers require catalysts. Any suitable catalyst can be employed. Common among catalysts used in the polymerization of the above listed reactants are catalyst AC '(trade name of the Monsanto Chemical Company for its approximately 50% solution of 2-methyl 2-amino propanol hydrochloride), other amine hydrochlorides, organic acids, inorganic acids, ammonium salts, and certain metal salts (Lewis acids) such as zinc nitrate, calcium chloride and magnesium chloride.

Animal glue suitable for use in accordance with this invention is an impure gelatin obtained from animal organs by boiling with water, straining and drying, and is usually supplied commercially in thin, hard and brittle cakes. Various glue or gelatin materials of animal orgin which are commercially available include acid-conditioned or limeconditioned collagen from frozen pork skins and limeconditioned collagen from calf skins, beef hides, and ossein. The molecular weight of this natural polymer varies from about 20,000 up to about 250,000. Animal glue is essentially composed of polyamides of certain alphaamino acids. It is believed that the amino acids are present not in the free state but rather as residues which are joined together by the elimination of water to form long polypeptide chains. Examples of some of the amino acids present in animal glue are glycine, proline, alanine, hydroxyproline, glutamic acid, arginine, aspartic acid, leucine, valine, phenylalanine, isoleucine, methionine, hydroxylysine, histidine, and tyrosine. Also it has been postulated that the animal glue molecules consist of single polypeptide chains terminated at one end by an amino group and at the other end by a carboxyl group. Description of useful animal glues can be found in Irvin Skeist, Handbook of Adhesives, 114-125 (1965); and in vol. 7, Kirk & Othmer, Encyclopedia of Chemical Technology, 207-215 (1951). 7

Animal glue is generally an amber colored material which exhibits a crystal-like appearance in the dried ground form. Having no definite melting point, animal glue decomposed when heated to its charring temperature. At temperatures of 100150 C., the glue exhibits a decreased solubility and in increased viscosity. Like most proteins, animal glue absorbs water readily and forms an elastic gel which readily melts at about 4050 C. to form a viscous solution having great adhesive properties. One of the characteristic properties of animal glue is its tendency to form reversible gels in aqueous solutions. Such gels are characteristic of increasing rigidity with lower temperatures and rising concentrations. Gelatin of animal glue solutions can be prevented or retarded by the addition of inorganic soluble salts, e.g. salts of the alkali earth metals. Also, certain organic substances such as urea, thiourea and phenyl exhibit this liquefying power. Aqueous solutions of animal glue are quite stable over a wide range of pH values, eg 3.0l0.0, without appreciable decomposition. The peptide units within the polymer of animal glue are subject to hydroylsis at temperatures above about 65 C. and boiling of an aqueous solution of animal glue breaks down both the viscosity and jelly strength thereof and, in the persence of mineral acids or alkalies, such decomposition is almost instantaneous. An example of a useful animal glue is obtained by the hydrolysis of collagen:

roz ms sa ar-l- 2 1o2 151 39 a1 wherein the chemical composition is:

Percent Carbon 5 1.29 Hydrogen 1 6.39 Oxygen 24.13 Nitrogen 18.19 100.00

The use of the glue in accordance with this invention is not restricted to any particular source of gelatin material. Nor is the Bloom value of the glue of particular significance. It has been found that any amount of glue will improve soil resistance, but that amounts in excess of about 5% based on the weight of the fabric will impart a normally undesirable stiffness to the fabric.

The effect of formaldehyde on glue is well known in the glue arts. Even a trace, .4% or more, based on the weight of the glue, will solidify the glue into a substance which is insoluble in water. As the proportion of formaldehyde to glue as the proportion of formaldehyde is increased; and as the proportion of formaldehyde exceeds about 50% the amount of the gelatin, there will be a marked deterioration in the soil resistance and soil release properties of the finished fabric as the fabric is repeatedly washed.

The amount of formaldehyde which will be absorbed by glue alone and which will provide maximum strength in the glue is within a range of 48%, based on the weight of the glue. This is the desirable amount of formaldehyde in the finish mixture when the fabric is comprised essentially of synthetic fibers. As the percentage of cellulosic fibers in a fiber blend is increased, however, the amount of formaldehyde which reacts with cellulose should be added to the amount absorbed by the glue in determining a theoretically ideal proportion. The amount of formaldehyde which will react with and cross link cellulose under resin-curing conditions is known to approximate 5.8% in the case of dry cellulose and from about .4% to about 1.5% in the case of swollen cellulose, these percentages being based on the weight of the cellulosic fiber.

Suitable plasticzers for the animal glue in accordance with the instant invention include all alcohols, but preferably one of the polyhydroxy alcohols, as, for example, sorbitol or glycerine. The plasticizers have no effect on the soil resistance or soil release properties of the fabric. Their only purpose is to prevent the glue from unduly adversely effecting the hand of the fabric. Therefore, where a soft hand is unnecessary or undesirable, the plasticizer may be omitted entirely. For most purposes, it has been found that a minimum of about 20% of a polyhydroxy alcohol based on the weight of the glue will provide a good hand in most fabrics. An excess in the amount of the alcohol plasticizer will not create an unsatisfactory product; however no useful purpose is served by including a polyhydroxy alcohol in excess of about 500% based on the weight of the glue.

According to this invention, the plasticizer is mixed with an aqueous solution of the animal glue, which mix-' ture,is, in turn, added to the resin formulation, followed by which the article is contacted with the mixture and subsequently cured. I

It may of course be desirable to add other agents to the finish mixture in order to impart particular results. The inclusion of a rust inhibitor may' be desirable where treated fabrics are likely to contact metals. A plasticizer or softening agent may also be included as an optional ingredient in order to provide a more desirable hand or texture to the treated fabric. It has been found that the cationic softening agent hydroxyl alkyl glyoxalidine can be employed for this purpose. Softening agents are normally employed in amounts of from about 1 to about based on the weight of the total composition.

Contacting the textile article with the finish mixture can be accomplished by immersion, padding, spraying, roll application and any other such process knownnin the textile art. The contacting should be for a sutficient time to completely wet and impregnate the article. For example a contact time within the range of from about 5 minutes to about 90 minutes will generally be adequate to wet the textile article. A contact time of about 30 minutes is ordinarily preferred. However, preferred contact time for padding is from a fraction of a second to two seconds.

Following impregnation with the described treating composition, the treated fabricis dried and heated to cause reaction of the resinformulation, in situ, and to cure the resinous finish. At the same time the formaldehyde which is inherent in the resin system, is released as a free aldehyde, all or some of which is absorbed by the animal glue, causing the concomitant solidification of the glue in its plasticized form. The drying and curing of a treated fabric may be accomplished in separate steps or in a single operation if preferred. When drying is carried out as a separate step it may be done either at normal ambient air temperatures or at elevated temperatures from about 200 F. to about 250 F., leaving a residual moisture content of 58%. Following the drying operation, whether it be accomplished at normal temperature or by heating, the dried impregnated textile is brought to a temperature within the range of frcin about 260 F. to 35011. The higher the temperature, the shorter is the period of heat treatment. Thus, drying the impregnated textile for minutes in an oven maintained at a temperature of about 210 F. followed by heating at'a higher temperature, for example, 8 minutes at 290 F; or for 4- minutes for 320 F., is generally effective in obtaining the desired results. These specific time and temperature periods are merely illustrative of those that can be employed.

Although as stated above, the application of this invention is especially suited and most eifective when used with cellulosic fibers because the principles of cellulose reactivity are involved in cross-linking the cellulose by means of its available hydroxyl groups which are reactive sites for the resin reactants, this process has w important significance in connection with the non-cellulosic or synthetic fibers in fabric blends, and even with respect to fabrics composed solely, or in part soley of synthetic fibers. Even witlrthe absence of available hydroxyl groups on the synthetic fibers, the use of the animal glue with its tendency to adhere to any fiber, creates, on the part of the non-cellulosic fibers a durable finish coating.

Permanent press finishes are most eifectively applied to fabric blends of cellulosic and non-cellulosic fibers because there is a significant strength loss on the part of cellulose when finished with the durable press finishers. Since this strength loss ranges from 40 to 50%, synthetic fibers of polyester, nylon or acrylics are commonly used to maintain within the finished product a strength that is sufficient for the prospective end use. Accordingly, a resin finish which has a lasting eifect on non-cellulosic fibers, aswell as cellulosic' fibers, is particularly useful in this new field. 7

The following examples will serve to illustrate specific embodiments of this invention.

Examples i Swatches of a broad-cloth fabric blend consisting of 65% dacron polyester and 35% cotton were contacted with the following finish mixtures by dipping the fabric followed by padding on a mangle to a 65% wet pick up.

Percent by weight ingredient a of fabric l0% solids solution of dihydroxy dirnethylol ethylene urea. 30% solids solution of zinc nitrate ethylene urea. 30% solids solution of 021012. Moropol 700- i i lSilkand 40 40% solids solution of dihydroxy dimethylol ethylene urea. 30% solids solution of zinc nitrate 30% solids solution of dlhydroxy dimethylol ethylene urea 30% solids solution of magnesium chloride 30% solids solution o r'dihydroxy dimethylol ethylene urea. 30% solids solution of magnesium chloride solids solution of dihydroixy dimethylol ethylene urea. 30% solids solution or magnesium chloride- Cirrasol PT 30% solids solution of dihydroxy dimc-thylol ethylene urea. I

80% solids solution of magnesium chloride Animal glue 30% solids solution of dihydroxy dimethylol ethylene urea. T

80% solids solution of magnesium chloride Animal gluon" Sorbitol 80% solids solution of dihydroxy dimcthylol ethylene urea.

' 80% solids solution of magnesium chloride Animal glue ,Sorhifnl GaC 10 Unfinished controL Nora-The above trade names are identified as follows:

FC-216 by 3M Company is. a S011 release additive containing a iluorocarbon compound of the same family as Scotchguard chemals.

Cirrasol PT by Imperial Chemical Industries Ltd. is a. soil release additive containing a polyester/polyethylene glycol copolymer and other undisclosedadditives.

Silkand 40 by Onyx Chemical Co. is a soitener of undisclosed composition.

Moropol 700 is a softener'based on low density polyethylene by Morotex Chemical Co.

read against a white background with a Photovolt Reilectance Meter (Model No. 610, Photovolt Corp., New York, N.Y.). These readings are as shown in Table 1 under original.

Each sample was then placed in a liter screw-cap jar containing 100 millimeters of a soiling solution, and the jar was agitated for a period of 5 minutes to insure that the sample was thoroughly saturated and well exposed to the mixture.

The soiling solution was prepared in the following manner. A 100 gram mixture consisting of Airborne soil 4 The above was mixed thoroughly and added to an equal volume of water at 130 F. in a Waring blender. After being homogenized for 15 minutes, the mixture was diluted to a liter and homogenized for another 15 minutes.

The samples were then removed from the screw-cap jars and passed through squeeze rolls with pressure adjusted on the rolls to provide cotton broad-cloth (3.1 oz./sq. yd.) with a wet pick-up of 70-80%. All samples were then hung in a circulating air oven set at 180-185 F. for minutes. After drying, all samples were washed in a Tergetometer (U.S. Testing Co.) at 130 F. for 10 minutes at a 30:1 liquor-to-fabric ratio using 1 gram per liter of Tide, a detergent soap manufactured by Proctor & Gamble. Samples were rinsed, dried and again measured for reflectance with the Photovolt Reflectance Meter. Results of the second sample readings are at Table 1 under whiteness after Soiling and Washing.

Soil resistance, as shown in the change column, must be compared with stain resistance. Although some control samples without animal glue showed excellent soil resistant properties, their stain resistance was poor as shown in Table 2.

The same 10 samples were stained with 2 drops of each of the following stains: motor oil, mustard, Crisco, 3-in-1 oil, and mineral oil. The stains were allowed to dry, after which the samples were washed as described above. After washing and drying, the darkest portions of the stains were compared with the gray scale for evaluating staining, as described in Section II of the 1965 Technical Manual of The American Association of The Textile Chemists and Colorists. The degree of staining of each sample is shown as follows:

TAB LE 2 Staining class Description 0. Slightly stained. Notic'eably stained.

D0. Heavily stained.

l Contained animal glue.

Any departure from the description herein that conforms to the present invention is intended to be included within the scope of the claims.

We claim:

1. A process for providing a soil resistant and soil release finish to a textile article comprising the steps of contacting said article with an aqueous mixture consisting essentially of (1) a resin-forming reactant selected from the group consisting of methylol urea, methylol melamine,

propylene urea, imidazolidone, methylol carbamate,

methylol uron, triazone and acetal,

(2) animal glue, and

(3) a polyhydroxy alcohol and then curing said resin.

2. The process of claim 1 wherein said article is a fabric.

3. The process of claim 1 wherein said article is a fabric consisting essentially of cellulosic fibers.

4. The process of claim 1 wherein said article is a blend of cellulosic fibers and non-cellulosic fibers.

5. The process of claim 1 wherein said article is a filament.

6. A process for providing a soil resistant and soil release finish to a textile article comprising the steps of contacting said article with an aqueous mixture consisting essentially of (1) a resin forming reactant selected from the group consisting of methylol urea, methylol melamine, imidazolidone, and methylol uron,

(2) a curing catalyst for said reactant (3) animal glue, and

(4) a polyhydroxy alcohol and then curing said resin.

7. The process of claim 6 wherein said article is a fabric.

8. The process of claim 6 wherein said article is a fabric consisting essentially of cellulosic fibers.

11 9. The process of claim 6 wherein said article is a References Cited blend of cellulosic and non-cellulosic fibers. UNITED STATES PATENTS 10. The process of claim 6 wherein said article is a filament 2,884,301 4/1959 Beaumont 8-1162, 11. A soil resistant finished textile article produced by 5 3,147,065 9/1964 Koshar, 8-1162 3,362,782 i/1968 Domemck 8116.3

the process of claim 1.

12. A soil resistant wrinkle-free finished fabric comprising cellulose fibers produced by the process of GEORGE F'LESMES Pnmary Exammer l i 1 B. BETTIS, Assistant Examiner 13. A soil-resistant wrinkle-free finished fabric com- 10 prising cellulosic fibers and synthetic fibers produced by the process of claim 1. B1l5.7, 116.2, 116.3, 127.6; 260-6; 117-139.4 

